The invention relates to a method of preparing samples in which at least one reaction agent and an initial sample are successively injected into a cartridge containing a column of powdery agent in such a manner as to cause the injected matter to pass through the column. The cartridge also has a bottom outlet orifice, and the product of the last passage through the column is collected separately and constitutes the final sample for analysis.
The reaction agents may be injected before or after the initial sample is injected. When injected before, the reaction agents serve to impregnate the column prior to the sample being injected; when injected after, they react with a column which has already been impregnated with the sample (and optionally, with other reaction agents).
The products of most of the passages through the cartridge are rejected: only the product of one specific passages is collected for analysis purposes. If the cartridges are reusable, the last material injected may be a cleaning or reconditioning agent.
One of the drawbacks of such a method lies in the time required for the sample and the reaction agents to pass through the column which they are to impregnate.
In order to accelerate such passages, suction means are generally connected in sealed manner to the bottom outlet orifices of the cartridges. The reduced pressure set up in this manner increases the speed at which injected material passes through the column and thus reduces the total time required for preparing a sample to be analyzed.
However, such suction means are bulky devices which need to match the size of the cartridges used and which need to be used in conjunction with a vacuum pump.
Preferred implementations of the present invention provide a method which reduces the total time required for preparing samples for analysis, and which avoids the need for suction means; the apparatus is thus simplified and does not require an additional source of energy such as required by a vacuum pump, and it is easily adapted to sample-preparing apparatus already in existence.